Counterfit Question

[Eldon]

From CardPlayer.com's Day 2 log
“Andy Bellan, author of Poker Nation, goes all-in preflop with A-Q and is called by 5-5. When the board comes 9-7-9-9-2, the pocket 5's are counterfeited, and out of genuine distaste for the beat the board put on his opponent he says "Unf____ing believeable!" The pocket 5's are eliminated, and Bellan doubles up, but the dealer immediately calls for the floor to report the cussing. So while Bellan stays alive, he's forced to sit out for the next 10 minutes.”

Why isn't the winning hand 99955 fullhouse?